1. Field of the Invention
The present invention relates to a liquid crystal display and a display panel thereof.
2. Discussion of the Background
A liquid crystal display (LCD) is one of the most widely used flat panel displays, and includes a pair of panels provided with field-generating electrodes, such as pixel electrodes and a common electrode, and a liquid crystal (LC) layer interposed between the two panels. The LCD displays images by applying voltages to the field-generating electrodes, which generate an electric field in the LC layer that determines the orientations of LC molecules therein to adjust polarization of incident light.
Among LCDs, a vertical alignment (VA) mode LCD, which aligns LC molecules such that the long axes of the LC molecules are perpendicular to the panels in the absence of an electric field, is of interest because of its high contrast ratio and wide reference viewing angle.
In the VA mode LCD, a wide viewing angle may be obtained by forming a plurality of domains having different alignment directions of the liquid crystal in one pixel.
The plurality of domains in one pixel can be realized by forming cutouts in the field-generating electrodes. In this method, a plurality of domains may be formed by aligning the LC molecules vertically with respect to the fringe field generated between the edges of the cutout and the field generating electrodes facing the edges.
However, the aperture ratio is decreased in this structure. Also, while the LC molecules disposed near the cutouts are easily aligned vertically with respect to the fringe field, the LC molecules disposed in the central portions of the domains far from the cutouts are affected by a random motion such that the response speed becomes slow and a domain of the opposite direction is formed such that an instant afterimage may appear.
As another means for forming the plurality of domains in one pixel, there is a light alignment method in which the alignment direction of the LC molecules and the alignment angle are controlled by irradiating light on the alignment layer. In the light alignment method, it is not necessary to form cutouts in the field generating electrode, so the aperture ratio may be increased and the response time of the LC molecules may be improved by a pretilt angle generated under the light alignment.
On the other hand, a VA mode LCD may have lower side visibility than front visibility, so one pixel is divided into two subpixels and different voltages are applied to the subpixels to solve this problem.
However, when the light alignment method is applied to the structure having two divided subpixels, the alignment direction determined by the light alignment may be different from the alignment direction of the LC molecules determined by the fringe field generated at a gap between the two subpixels of the LCD such that texture may be generated. The texture decreases transmittance and may appear as a stain such that the display characteristics of the LCD may be deteriorated.